8 Journal of Comparative Neurology. 



ance theory in its broadest expression. Marshall considers that 

 the fact that pain accompanies destruction of tissue is fatal to the 

 second clause of this theory. We should add that the evidence 

 shows that nearly all if not all nervous functioning consists of 

 rapid alternation of the two processes of metastasis and assimila- 

 tion and that pleasurable excitements are due to such oscilla- 

 tions while pain may result from interference in the free func- 

 tioning and transference of energy. 



One of the most recent theories of pleasure-pain is that 

 proposed by Mr. B. I. Oilman in a series of lectures published 

 in a syllabus in the American Journal of Psychology, VI, i. 

 This theory of habit assumes that "the source of all pleasure 

 is the performance by the nerves of activities which have once 

 become familiar to them and that pain has its source in a viola- 

 tion of nervous habitude." Thus expressed it is a physiological 

 theory closely associated with the resistance theory advocated 

 by the writer. It is, however, extended as follows: "Any 

 presentation correlated with a bodily process that tends to fix a 

 habit (increases a trace [i. e. a vestige]) is pleasurable ; while any 

 presentation correlated with a bodily process that tends to loosen 

 a habit (decreases a trace), is painful." Note in respect to this 

 theory that such nervous processes as would increase a trace 

 must necessarily be of super-medium nature, they must be un- 

 usually strong and therefore consume reserve force (as Marshall). 

 On the other hand those which remove vestiges would be such 

 as pass by explosive outbreak across the ordinary channels and 

 at the same time infringe on the reserve cell content. The pro- 

 cess devours not only the interest but the capital of the organ- 

 ism and with the latter goes the vestiges it may contain. 



It will be seen, however, that this theory fails when applied 

 closely to the simple sensuous pleasures and pains. As Oilman 

 points out, his theory agrees in part with Aristotle's, who re- 

 marks that pleasure is the sign of the perfection of an act as the 

 blooming cheek is of health, and with Herbart's, who says 

 "By pleasure, therefore, I signify a passive state wherein the 

 mind passes to a greater perfection." 



But Oilman defines these ideals as laid down by passed ex- 



